Method for decoding digital data and data managing device

Abstract

A method for encoding or decoding digital data, a data dissemination device and a data managing device are provided. The method for encoding digital data includes the following steps. A digital data is received. A sign data is encoded into the digital data through a linear combination operation to obtain an encoded digital data, wherein the size of the digital data is not changed after the encoding process. The encoded digital data is disseminated.

What is claimed is: 
     
       1. A method for decoding digital data capable of tracking data dissemination device, comprising:
 (a) receiving a digital data; 
 (b) decoding a correct codeword from the digital data and identifying at least two error positions of at least two error digits by a linear code decoding algorithm, wherein different error position denotes different sign data; and 
 (c) tracking at least two dissemination devices according to the at least two error positions. 
 
     
     
       2. The method for decoding digital data capable of tracking data dissemination device according to  claim 1 , wherein in the step (a) and the step (b), the digital data and the sign data are binary data or are elements belonging to a finite field GF (p n ). 
     
     
       3. The method for decoding digital data capable of tracking data dissemination device according to  claim 1 , wherein in the step (b), the correct codeword is decoded from the digital data through a parity check matrix. 
     
     
       4. The method for decoding digital data capable of tracking data dissemination device according to  claim 1 , wherein in the step (a), the digital data comprises an advertisement. 
     
     
       5. A data managing device, comprising:
 an input unit used for inputting a digital data; 
 a decoding operation unit used for decoding a correct codeword from the digital data and for identifying at least two error positions of at least two error digits by a linear code decoding algorithm, wherein different error position denotes different sign data; and 
 a tracking unit used for tracking at least two dissemination devices according to the at least two error positions. 
 
     
     
       6. The data managing device according to  claim 5 , further comprising:
 a storage unit used for storing a parity check matrix, wherein the decoding operation unit decodes the error position from the digital data through the parity check matrix.